The HP-38G Graphing Calculator and You -------------------------------------- Well, the other day i was looking around at stuff in my room, and my eyes fell upon my calculator. It was an expensive one, over $100, and it occurred to me that whatever price Hewlett Packard was going to charge me for their Connectivity Kit (which links the calculator to your Windoze computer) was too much. So, i did some playing around, and found that for the low low price of free, i could do the same myself. DISCLAMER: if you break stuff, it's not my fault, and i think you should cry. Part I -- The Cable ------------------- This was the most challenging part. What you need... HP-38G Graphing Calculator (duh) Serial Mouse (that you don't mind getting butchered) --or-- CD-ROM Audio Cable (with the smaller type plug) DB-9 Female plug Ok, look at your calculator face on (with the IR-Port and plug facing you) Should look something like this... ------------------------------------------------------------------ | | | o o o o o ________ | | * * * * o |________| | ------------------------------------------------------------------ (kinda, well i suck at ascii art) Now, out of the 10 pins there, only 4 are used. The pins that are used are the ones represented as stars. Now what you do depends on which cable you have. Mouse cable, part A, audio cable, part B. I used part A because i had a mouse lying around, but no audio cable. Don't worry, they are both easy. [Part A] Ok, open up your mouse... you will find that the cable plugs into one of the circuit boards. Unplug it. You will find that you can plug it into those four pins on your calculator, don't force it, and you may need to trim some plastic. Then, what you want to do is reconfigure the wires so they correspond to this table... HP-38G | DB-9 -------+----- 1 |metal shell (optional) 2 |pin 2 3 |pin 3 4 |pin 5 -------+----- Plug one end into your computer, plug the other into your calculator, and skip to the software part. [Part B] Ok, first all, cut off the CD-ROM end of the cable. then, you want to wire up your cable so it corresponds to the above table. Quite simple, really. Now plug them both in... Part II -- The Software ----------------------- Here you have two options. You can use HP's own software (available on hackcanada.com), or if you don't use windoze, kermit. The HP Software (which i have never used), i assume to be user friendly, and chances are if you are making your own cable and other -hard- things, you can figure it out anyway. Kermit, on the other hand can be a bit more difficult. First, get a working copy. It is available at the following site. http://www.columbia.edu/kermit/ Now, once you get a prompt in kermit, type the following... SET MODEM TYPE DIRECT SET PORT [whatever, in *nux don't forget about /dev/ttySx] SET SPEED 9600 SET CARRIER-WATCH OFF SET FLOW NONE SET PARITY NONE SET BLOCK 3 SET CONTROL PREFIX ALL Now, what this does is sets up kermit to use a direct connection, 9600bps, to not care about the carrier-detect line, no flow control, no parity. The last option is only really necessary if you are using kermit under windoze, but if you are doing that, then you might as well just use HP's own software, it's idiot friendly... Part 3 -- The Connection ------------------------ Go on the internet, download some game. Unzip it into whichever directory. In kermit, cd to that directory, and type 'SERVER'. This makes sending and receiving files much easier. On your calculator, press [LIB], then [RECV]. Select "Disk Drive". The applet's you have in the current directory will show up on the screen, select it, press enter, and they are sent over. To send text files or programs, do the same, just in the respective area of the calculator. If there is a problem, make sure your connections are nice and tight. Make sure your cable is plugged into the right part of the calculator, and make sure you entered the settings for kermit correctly. I'll add more when i learn more. The P0pe bsmiley@hotmail.com 08/19/99